are watching tonight. Red-hot race for the white house. A new abc news/washington post poll out today shows the two men deadlocked. Governor romney on top by a hair tonight. Which group of voters could still break this tie? 13 days until americans go to the polls. It's your voice your vote. And david muir is in the battleground state of iowa tonight. David? Reporter: Diane, good evening. The women's right to choose. Front and center in the news because what a senator candidate said in a debate. He was just endorsed by mitt romney. Reporter: Tonight they are words that have caused a firestorm - from a senate candidate who just days ago put up this ad - an endorsement from mitt romney. This fall I'm supporting richard mourdock for senate. Reporter: Now that senate candidate, reigniting a flashpoint -- when asked if he supported abortion in cases of rape, he said this -- I came to realize that life is a gift from god and I think even when life begins in that horrible situation of rape that it is something that god intended to happen. Reporter: Within hours, the romney campaign trying to distance itself, saying those comments don't reflect romney's views. But, romney would continue to support him. For mitt romney, it complicates his final push to appeal to more women voters. President obama leads among women. But among white, married middle-class women, romney is ahead by more than 20 points in our newest poll tonight. Increasing that number could key the victory. Romney speaking of women on the trail today in nevada -- I think of the single women right now raising a child or two or three, so that she could put a good meal on the table. Reporter: And in the debate, a more moderate view -- world view -- we want a peaceful planet. Reporter: A tone that might but, on the delicate issue of abortion, shifting tone, more challenging -- romney during the primaries -- do I believe the supreme court should overturn roe v. Wade? Yes I do. Reporter: Then, just this month, he told the "des moines register" -- there's no legislation with regards to abortion that I'm familiar with that would become part of my agenda. Reporter: The president calling that shifting tone an issue of trust, today in iowa -- you can choose to turn back the clock ears on women and immigrants and gays or, in this election, you can stand up for the kind of america that we embrace everybody. Reporter: Tonight, the obama out with its first campaign featuring michelle obama. An effort to reassure voters, among them women, hoping they'll stick with the president. The obama campaign tried to accomplish two goals with that new ad with michelle obama, troo together reach those women who might be considering mitt romney, trying to bring them back to president obama. Meantime here tonight, mitt romney will be here in iowa, moments from now, he'll end the night in the key battleground state of ohio. Thank you, david, on the

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